Risk assessment information page v1.2 (16/03/2011)

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Information about GB Non-native Species Risk Assessments

The Convention on Biological Diversity (CBD) emphasises the need for a precautionary approach towards non-native species where there is often a lack of firm scientific evidence. It also strongly promotes the use of good quality risk assessment to help underpin this approach. The GB risk analysis mechanism has been developed to help facilitate such an approach in Great Britain. It complies with the CBD and reflects

standards used by other schemes such as the Intergovernmental Panel on Climate Change, European Plant Protection Organisation and European Food Safety Authority to ensure good practice.

Risk assessments, along with other information, are used to help support decision making in Great Britain.

They do not in themselves determine government policy.

The Non-native Species Secretariat (NNSS) manages the risk analysis process on behalf of the GB

Programme Board for Non-native Species. Risk assessments are carried out by independent experts from a range of organisations. As part of the risk analysis process risk assessments are:

Completed using a consistent risk assessment template to ensure that the full range of issues recognised in international standards are addressed.

Drafted by an independent expert on the species and peer reviewed by a different expert.

Approved by an independent risk analysis panel (known as the Non-native Species Risk Analysis Panel or NNRAP) only when they are satisfied the assessment is fit-for-purpose.

Approved for publication by the GB Programme Board for Non-native Species.

Placed on the GB Non-native Species Secretariat (NNSS) website for a three month period of public comment.

Finalised by the risk assessor to the satisfaction of the NNRAP.

To find out more about the risk analysis mechanism go to: www.nonnativespecies.org

Common misconceptions about risk assessments

To address a number of common misconceptions about non-native species risk assessments, the following points should be noted:

Risk assessments consider only the risks posed by a species. They do not consider the

practicalities, impacts or other issues relating to the management of the species. They therefore cannot on their own be used to determine what, if any, management response should be undertaken.

Risk assessments are about negative impacts and are not meant to consider positive impacts that may also occur. The positive impacts would be considered as part of an overall policy decision.

Risk assessments are advisory and therefore part of the suite of information on which policy decisions are based.

Completed risk assessments are not final and absolute. Substantive new scientific evidence may prompt a re-evaluation of the risks and/or a change of policy.

Period for comment

Draft risk assessments are available for a period of three months from the date of posting on the NNSS website*. During this time stakeholders are invited to comment on the scientific evidence which underpins the assessments or provide information on other relevant evidence or research that may be available.

Relevant comments are collated by the NNSS and sent to the risk assessor. The assessor reviews the comments and, if necessary, amends the risk assessment. The final risk assessment is then checked and approved by the NNRAP.

*risk assessments are posted online at:

https://secure.fera.defra.gov.uk/nonnativespecies/index.cfm?sectionid=51 comments should be emailed to [email protected]

Risk assessment information page v1.2 (16/03/2011)

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GB NON-NATIVE ORGANISM RISK ASSESSMENT SCHEME

For more information visit: www.nonnativespecies.org

Name of Organism: Vespa velutina nigrithorax, The Asian hornet

Objectives: Assess the risks associated with this species.

Version: Original draft 25/07/11

Author:

Prepared by Gay Marris¹, Mike Brown¹ and Andrew G. Cuthbertson²

1. National Bee Unit, Fera

2. Crop and Food Security, Fera

Suggested citation: Marris et al (2011). GB Non-native Organism Risk Assessment for Vespa velutina nigrithorax. www.nonnativespecies.org

SECTION B: Detailed assessment of an organism’s probability of entry, establishment and spread and the magnitude of the economic, environmental and social consequences

Probability of Entry RESPONSE UNCERTAINTY COMMENT

1.1 List the pathways that the organism could be carried on. How many relevant pathways can the organism be carried on?

Many - 4 Low - 0 1. Natural spread of pest itself by flight.

2. Movement of wood, wood products and bark (which provide suitable harbourages for hibernating inseminated V. velutina queens).

3. Movement of man-made goods that provide suitable harbourages for hibernating inseminated V. velutina queens (e.g. ceramic pottery associated with garden trade).

4. Movement of soil associated with plant trade (harbourage for hibernating inseminated V. velutina queens; potentially nesting stages in soil).

5. Fruit imports (e.g. grapes) (could transport adult V.

velutina using fruit as food source).

6. Movement on freight containers and transport vehicles themselves (harbourages for hibernating inseminated V.

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velutina queens; could also carry worker hornets).

7. Movement of honey bees: queens and packaged bees (workers) for the purposes of trade (could transport adult V. velutina).

Of the above seven pathways, no.s 1. and 2. (natural spread by the pest itself and transport of hibernating queens with e.g.

comparatively large trees with bark) are considered to be of relatively high importance; pathway no.s 3. and 5. (with other (man-made) hibernation sites, or on fruit/cut flowers) are considered to be of intermediate importance; pathway no.s 4., and 6. (movement on soil or on freight/other transport vehicles) are considered to be of comparatively low importance; pathway 7. (movement with traded honey bees) is included for sake of completeness, but is considered to be least likely of all seven.

1.2 Choose one pathway from the list of pathways selected in 1.1 to

begin the pathway assessments.

Pathway 1. Natural spread of pest itself by flight.

1.3 How likely is the organism to be associated with the pathway at origin?

Very likely – 4

Low – 0 The current (2010 provisional) European range of the Asian hornet is illustrated below (Map courtesy of Claire Villemant, Muséum National d’Histoire Naturelle, Paris, France (MNHN)). Vespa velutina is present (2010 estimate) in at least 39 départements of France (Villemant et al., 2011a), and was confirmed in North East Spain for the first time in November 2010 (Castro & Pagola-Carte, 2010) in Irun, Hondarribia and Oiartzun. Current researchers predict that many countries in Europe including the UK are climatically suitable for establishment of V. velutina (Rome et al., 2009;

Villemant et al., 2011b) and spread within France and into Spain has been very rapid (Villemant et al., 2011a). Asian hornets have been present in Brittany since 2008 – this region immediately abuts Basse Normandie, the coast of which is comparatively closer to southern England.

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The shortest distance between England and France over the English Channel is 34km, between Dover and Cap Gris Nez.

V. velutina is present in at least one coastal area of France (Northern Brittany: Ille-et-Vilaine since 2008; Côte-d’Armor, since 2010) In the (highly likely) event that V. velutina increases its European range, and also spreads to other more northerly coastal regions of France, then in theory inseminated Asian hornet queens could fly across the Channel. (Asian hornet workers could also travel by this Pathway, but these do not pose a threat of establishment in the Risk Assessment area, as they are incapable of establishing new colonies). (ii) Distances covered by adult V. velutina in single flights are unknown, but unpublished data on V. velutina’s flight

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capacity in the laboratory suggests that males can fly dozens of km in one flight, and workers several km. Queens are believed to be even more efficient flyers but have not been tested yet (pers. comms. Marc Kenis, CABI Switzerland). (iii) Research into flight capacity of Asian hornet queens is ongoing (pers. comm. Quentin Rome, MNHN) - It is possible that certain weather conditions (wind direction) will assist natural spread (pers. comm. Claire Villemant MNHN).. (iv) There are no confirmed records of other social Hymenoptera crossing from continental EU to the UK via this Pathway, but the Median wasp, Dolichovespula media, a non-native species established in the UK since 1980, was first recorded in the coastal area of East Sussex (Falk, 1982), implying that it flew across the Channel from mainland Europe. (v) There are numerous records of other insects (butterflies, ladybirds etc.) crossing the English Channel each year, sometimes in vast numbers:

(http://www.nationalinsectweek.co.uk/facts.php) 1.4 Is the concentration of the organism on the

pathway at origin likely to be high?

Moderately likely – 2

Low – 0 (i) V. velutina is present in at least one coastal area of France (Northern Brittany: Ille-et-Vilaine since 2008; Côte-d’Armor, since 2010) , and is highly likely to reach other coastal areas in the near future (potentially in 2011). (ii) The concentration of V. velutina on the Pathway at origin will depend on the size of the hornet population in any given area - as many as ten V.

velutina nests have been reported in a radius of just 600m (Villemant & Haxaire, 2007) (iii) Records of hornet species forming swarms are rare, but swarms of the European hornet V. crabro may contain several thousand individual queens (Mulhauser & Vernier, 1994) – group migrations, although rare, do occur in the native hornet, and may occur in V.

velutina. (iv) An account of an attack by V. velutina in France described the hornets as originating from a ―single swarm‖

(Bond, 2009), but frequency of swarming behaviour in Asian hornets is unknown. It is unlikely that a swarm of hornets could cross the channel in a single flight. (iv)

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1.5 How likely is the organism to survive existing cultivation or commercial practices?

N/A No cultivation or commercial practices associated with this Pathway.

1.6 How likely is the organism to survive or remain undetected by existing measures?

N/A No detection measures specifically associated with this Pathway.

1.7 How likely is the organism to survive during transport/storage?

Likely – 2 Low – 0 (i) There is no data available on the likelihood that V. velutina queens could survive a non-stop flight over a distance of 34km (minimum distance across English Channel). However, there are numerous examples of other insects crossing the Channel by their own means (see 1.3 above, and http://www.nationalinsectweek.co.uk/facts.php (ii) The Median wasp, Dolichovespula media, a non-native species established in the UK since 1980, was first recorded in the coastal area of East Sussex (Falk, 1982), implying that it arrived from Europe having flown across the channel. (iii) Under normal circumstances, the lifespan of an adult female V. velutina is 24-142 days, and an adult male 4-60 days (Dong

& Wang, 1989), but this assumes access to food, water and shelter.

1.8 How likely is the organism to

multiply/increase in prevalence during transport /storage?

Very unlikely – 0

Low – 0 Conditions during cross-Channel flight completely incompatible with multiplication. Prevalence would be more likely to decrease, due to individual hornets dying during the journey (adverse weather, exhaustion etc.).

1.9 What is the volume of movement along the pathway?

Very low – 0 Low – 0 Unknown. Likely to be low.

1.10 How frequent is movement along the pathway?

Very

infrequent – 0

Low – 0 Unknown. Likely to be low.

1.11 How widely could the organism be distributed throughout the Risk Assessment area?

Limited distribution – 1

Low – 0 Cross-Channel entry into the UK via natural spread would mean that V. velutina would initially be most likely to arrive in southern England.

1.12 How likely is the organism to arrive during the months of the year most appropriate for establishment ?

Very likely – 4

Low – 0 (i) The active months for V. velutina are between April and November, the peak being August/September (Abrol, 1994;

HaiQin et al., 2006; Mollet et al., 2006; 2007; Chauzat &

Martin, 2009) – so adult Asian hornets would be most likely

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to arrive during these months via this Pathway. (ii) Establishment in the Risk Assessment area via this Pathway can only occur if the hornet in question is an inseminated queen – only this life stage can found a new colony. (iii) Inseminated queens arriving early in the season (spring) could establish new nests. (iv) Inseminated queens arriving in the autumn could overwinter in the UK. (v) Irrespective of the date of arrival, worker hornets would not be expected to establish in the Risk Assessment area – this life stage is not capable of reproducing, and is also dependent on a colony of co-workers for survival.

1.13 How likely is the intended use of the commodity (e.g. processing, consumption, planting, disposal of waste, by-products) or other material with which the organism is associated to aid transfer to a suitable habitat?

N/A No commodities associated with this Pathway.

1.14 How likely is the organism to be able to transfer from the pathway to a suitable habitat?

Very likely – 4

Low – 0 (i) Adult workers: The length of time which an Asian hornet worker can survive away from her colony is unknown – an individual arriving in the Risk Assessment area via this Pathway would only be expected to survive in the short term, depending on access to food and shelter, but she would not be capable of independent existence long term - this life stage is also dependent on a colony of co-workers for survival. (ii) Queen hornets are highly mobile, and very adaptable – they are unlikely to have to travel far from the Pathway to locate suitable habitats. As long as they have access to water, nesting material (wood), and food – their needs will be met - Food must provide a source of carbohydrate for founder queens (e.g. fruit/nectar) and source of prey (which does not have to be honey bees, but can be other locally available insects) for developing hornet larvae (Matsuura & Yamane, 1990; Perrard et al., 2009) - all resources to meet V.

velutina’s basic requirements are widespread throughout the UK, including areas associated with this Pathway (Southern coastal regions).

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1.2 Choose one pathway from the list of pathways selected in 1.1 to

Pathway 2. Importation of wood and wood products (provide suitable harbourages for hibernating inseminated V. velutina queens).

Likely - 3 Medium - 1 The native geographic range of Vespa velutina includes Bangladesh, Bhutan, China (including Hong Kong), India, Indonesia (Java, Sumatra, Sulawesi), Korea Republic, Laos, Malaysia, Myanmar, Thailand and Vietnam. This distribution is illustrated in the map below. Asian hornets are now present in France and northern Spain (see map in Pathway 1., response 1.3, above).

Map of Asian range of Vespa velutina

The UK imports a wide variety of commodities from these EU and non-EU countries where V. velutina is known to be

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present.

Inseminated queens of V. velutina search for small, well- insulated crevices in which to hibernate. Each individual has the potential to found an entire new colony. V. velutina queens have been found hibernating underneath tree bark (Dong & Wang, 1989; Villemant & Haxaire, 2007; Chauzat &

Martin, 2009). There is an extremely broad range of tree species and wood products (e.g. timber, wooden crates etc.) that offer potentially suitable hibernation sites of this type. A variety of trees, wood and wood products are imported into the UK, and some of these come from countries where V.

velutina is known to be present. This Pathway has multiple origins. It is not possible to be specific about likelihood of V.

velutina queens associating with any particular tree species, in any given country – V. velutina’s preferences for particular tree species are unrecorded.

1.4 Is the concentration of the organism on the pathway at origin likely to be high?

Unlikely - 1 Low - 0 Hibernating adult V. velutina can cluster in small groups of up to 3 individuals (Mollet et al., 2006; 2007; Chauzat & Martin, 2009), although size of congregations may vary depending on the commodity in question. A relatively small crevice could harbour several individuals. Several overwintering Asian hornet queens were found in a single oak tree, in cavities left by beetle larvae (Mollet et al., 2006; 2007). The concentration of V. velutina on the Pathway at origin will also depend on the size of the hornet population in any given area - as many as ten V. velutina nests have been reported in a radius of just 600m (Villemant & Haxaire, 2007) – this is a higher nest concentration than observed for native European hornet V. crabro (Larsson, 1988).

Moderately - 2

Low - 0 Likelihood of survival depends on growing and felling conditions, whether or not the tree species is controlled (see Question 1.6, below), its country of origin (EU v. 3^rd country), and the type of wood product: (i) It is highly unlikely that V.

velutina would survive processes of bark removal or wood-

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chipping; (ii) It is probable that V. velutina would not survive processes such as wood-treatment with preservatives or stains;

(iii) It is entirely possible that V. velutina would survive in untreated fuel-wood/logs; (iv) V. velutina queens seeking refuge in wood after it has been processed (e.g. a pile of chipboard, wooden packing crates etc.), would be expected to survive; (v) Some (but not all) imported wood and wood products are treated to eradicate tree pests. e.g. kiln-drying, fumigation or heat treatment (56^oC, 30 minutes) (see response to Question 1.6 below). It is likely that kiln-drying would be lethal to V. velutina adults, as it is used to effectively control a variety of tree pests, including bark beetles (Forestry Commission, 2007). Asian hornets will die at a temperature of 45^oC, as demonstrated by the natural and lethal ―heat-balling‖ defense response of A. ceranae (Ono et al., 1995; Ken et al., 2005; Chauzat & Martin, 2009); (vi) Uncontrolled timber imports may not be treated, allowing V.

velutina to survive; (vii) in cases where whole living trees are harvested (e.g. olive trees for garden trade), V. velutina would be expected to survive.

Likely - 3 Low - 0 Import regulations and potential detection measures depend on tree species, country of origin and nature of wood product.

These are summarised in Forestry Commission Plant Health Guide Importing wood, wood products and bark (Forestry Commission, 2007) and also Plant Health Directorate 2000/29/EC.

Wood imports from third countries: Tree genera originating from relevant third countries (i.e. those within the Asian hornet’s range), which are currently prohibited under EU legislation include all conifers, sweet chestnuts and citrus trees. (It is anticipated that in 2010 import of Acer from China will also banned). Some other species are permitted, but only under specified conditions (e.g. that the tree is dormant, and not in leaf). Examples of this type include

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certain oaks and poplars. However, under existing legislation (Plant Health Directive 2000/29/EC), the majority of tree species can be imported into the Risk Assessment area.

Relevant wood materials and products (i.e. those that could provide suitable hibernation niches for V. velutina queens) of controlled tree species include: fuel wood in logs; isolated tree bark; wood waste and scrap; wood ―in the rough‖ (treated or otherwise) with bark still on; railway sleepers; wooden packing cases, boxes, crates, drums, pallets etc.; casks, barrels, vats and tubs; prefabricated buildings of wood. These products can be imported into the UK if they are certified as meeting at least one of the following requirements: bark-free, kiln-dried to <20% moisture content, subjected to an approved fumigation regime, or heat-treated to a minimum core temperature of 56^oC for at least 30 minutes. Plant health checks of controlled imports from third countries are made at approved points of entry into Great Britain (see www.forestry.gov.uk/planthealth). These include airports, docks etc. In a typical year 1,000,000m³ of controlled timber goods originating from third countries are officially inspected, corresponding to 5,000 separate plant health checks.

Inspectors check paperwork to ensure that certification of above treatments is in order, and physically examine consignments, to ensure freedom from tree pests (Forestry Commission, 2007). If landing requirements are not met, the inspector can prohibit landing, order re-export of the consignment, or destruction of the consignment (by burning).

Key points: (i) The fact that above controlled commodities lack bark and/or must be treated prior to entry greatly reduces the probability that V. velutina will survive existing management practices imposed on third country wood imports; (ii) Only a proportion of any consignment (a representative sample) of controlled wood/wood products from a third country may be inspected, and V. velutina is not a tree pest; if present in any numbers these hornets are likely to

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be detected, but they are not specifically targeted during plant health inspections; (iii) Many trees/wood products from third countries are not subject to control, and will not be inspected/treated as above – V. velutina could enter undetected through such Pathways.

Wood imports from EU: These are subject to far fewer restrictions and checks. Controls focus solely on conifers and sweet chestnut. To ensure freedom from certain listed tree pests (but not V. velutina), these must be bark-free or kiln dried. Alternatively, they can enter the EU with bark and without having been treated, as long as they come with a statement that they originate from an area free of named tree pests. When controlled woods/wood products originate within the EU, they are not inspected at approved points of entry, and are able to travel to their destination unchecked as long as they have appropriate documentation. Wood importers must register as Forestry Traders, and it is their responsibility to check that importation requirements are met.

Key points: (i) V. velutina is not a quarantine tree pest or disease; if present in any numbers these hornets may be detected at final destination, but they are not specifically targeted during inspections of controlled wood products entering from the EU. (ii) the vast majority of wood entering from the EU is not subject to any control, and will not be inspected – for example, importation of large mature olive trees from continental Europe (including France and Spain), complete with bark, is completely legal and unregulated.

Such trees do not require a plant passport and can move freely from France and Spain to the UK without inspection. Mature olive trees imported from EU can be purchased from many garden centres throughout the UK.

Very likely - 4

Low - 0 Specific data re. duration of Asian hornet hibernation under natural circumstances is limited, but it typically lasts about 4 months (Dong & Wang, 1989) – far longer than the typical duration of transportation for wood imports. Length of

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storage for any commodity depends on goods involved.

Very unlikely - 0

Low – 0 Hibernating queens of V. velutina are dormant – not in physiological state at which multiplication will occur.

High - 4 Low - 0 A large proportion of the wood and wood products consumed in the UK are imported, from a range of different countries.

(Information on imports can be obtained from the Overseas Trade Statistics compiled by HM Revenue and Customs). In a typical year, the UK imports approx 50 million m³ of raw wood material equivalent (WRME) underbark. The majority of this arrives as coniferous sawnwood, paper/paperboard (e.g. in form of packaging materials), or as wood-based panels. 17% of the UK’s plywood imports come from Indonesia and China (V. velutina present); 27% of imported particle- board comes from France (all figures Forestry Commission, 2005). In the UK: almost 90% of softwood used in construction is imported; 70% of softwood pallets use imported wood; approximately 20% of fencing/outdoor softwood is imported (Moore, 2009). Volume of trade in living mature trees from V. velutina’s current range (especially France and Spain) is unknown.

Very frequent – 4

Low – 0 Movement of wood, wood products and bark into the Risk Assesment area occurs throughout the year.

Very widely – 4

Low – 0 Controlled wood and wood products from third countries must arrive through approved points of entry into Great Britain (see www.forestry.gov.uk/planthealth). These include over 70 ports and airports across England. Uncontrolled wood imports from third countries, and all wood imports from the EU can travel directly to their destination – potentially anywhere in Risk Assessment area.

Very likely – 4

Low – 0 Wood and wooden commodities may potentially be brought in at any time, including months most suitable for establishment.

Risk greatest with imports in spring – just prior to completion of hibernation and emergence of queens ready to found new colonies.

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Medium – 1 Depends on the type of wood/wood product - Certain commodities (e.g. olive trees) will be placed out doors, straight into a suitable habitat for V. velutina (i.e. garden).

Timber intended for outdoor use will also aid transfer – the UK imports a large volume of softwood for use in fencing (see response to Question 1.9, above).

Low – 0 (i) Depends on the type of commodity imported and where it will be used – e.g. indoors versus outdoors. Transfer will be much more likely if goods are placed outside and the hornets are not confined on emergence. (ii) The majority of inspections of controlled wood/wood products entering the UK from third countries are made in the open, ―at the quayside‖ (Ian Brownlee, Forestry Commission, pers. comm., 2010); this fact could impact on likelihood of escape of adult V. velutina. (iii) Storage conditions of wood and wood products post-inspection will depend on their intended use.

(iv) Provided a mated queen remains undisturbed long enough to complete hibernation (i.e. wood commodity in which she is concealed is not processed, but stored), then she can emerge to found a new colony. Queen hornets are highly mobile, but are unlikely to have to travel far from the Pathway to locate suitable habitats. (See Pathway 1. Question 1.14). V. velutina is also very adaptable - all of this hornet species’ basic requirements are widespread throughout the UK, including areas associated with this Pathway. (v) The distribution of the native European hornet V. crabro within the Risk Assessment area is largely confined to England south of Yorkshire and Wales (Edwards, 1997) – assuming requirements of V.

velutina are similar, then likelihood of transfer to a suitable habitat from this pathway will be greatest within these areas.

1.2 Choose one pathway from the list of pathways selected in 1.1 to

Pathway 3. Movement of man-made goods that provide suitable harbourages for hibernating inseminated V. velutina queens (e.g. ceramic pottery associated with garden trade).

Unlikely High – 2 Inseminated queens of V. velutina do not just use ―wild‖ sites in which to hibernate; they will also use man-made sites as

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long as these provide small, well-insulated refuges in which they can hide away over the winter months (Dong & Wang, 1989; Villemant & Haxaire, 2007; Chauzat & Martin, 2009).

The range of commodities that are suitable hibernation sites is extremely broad, so is not possible to be specific about likely concentration of V. velutina at the potentially multiple origins of this Pathway. It is believed that hibernating queens of V.

velutina were imported into France from Yunnan (China) in ceramic bonsai pots (Villemant el al., 2006a) (see response to Question 1.29, below).

Unlikely Medium - 1 Hibernating adult V. velutina can cluster in small groups of up to 3 individuals (Mollet et al., 2006; 2007; Chauzat & Martin, 2009), although size of congregations may vary depending on the commodity in question. A relatively small volume crevice could harbour several individuals, each mated queen having the potential to establish an entire new hornet colony. Since the range of commodities suitable for hibernation (any dark, well-insulated, dry substrate) is extremely broad, it is not possible to be specific about likely concentration of V.

velutina at the potentially multiple origins of this Pathway.

Likely – 1 High – 2 This Pathway has multiple origins, and is likely to have a range of different commercial practices associated with it. It is therefore impossible to anticipate chances of V. velutina surviving in each case. However, the case of introduction of V. velutina into France demonstrates that the Asian hornet survived the Pathway of importation on ceramic pottery (see response to Question 1.3, above).

Likely - 1 Medium - 1 This Pathway involves a wide range of commodities, likely to be subjected to a correspondingly diverse array of different inspection procedures. It is unknown whether ceramic pottery imported from EU or third countries into the Risk Assessment area are routinely inspected. However, the case of introduction of V. velutina into France demonstrates that the Asian hornet was not detected on this commodity (see response to Question 1.3, above). It is possible for ceramic

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garden goods to be imported from France, Spain or elsewhere in mainland Europe to the UK without any inspection that would reveal hibernating V. velutina.

Likely – 2 Low - 0 The example of introduction of V. velutina into France on (presumably untreated) ceramic pottery demonstrates its ability to survive during transport/storage. Specific data re.

duration of Asian hornet hibernation under natural circumstances is limited, but it typically lasts about 4 months (Dong & Wang, 1989) – far longer than typical duration of transportation for most imports. Length of storage for any commodity depends on goods involved.

N/A Hibernating queens of V. velutina are dormant – not in physiological state at which multiplication will occur.

High - 2 Low - 0 Since the range of commodities suitable for hibernation (any dark, well-insulated, dry substrate) is extremely broad, it is not possible to be specific about volume of movement along this Pathway. However, numerous suitable commodities (in terms of hibernation refuge sites offered) are imported into the UK in bulk every year.

Frequent -2 Low - 0 This Pathway has multiple origins. It is not possible to be specific about frequency of movement. However, numerous suitable commodities (in terms of hibernation refuge sites offered) are imported into the UK in bulk throughout the year.

Very widely – 4

Low – 0 This Pathway has potential to introduce V. velutina throughout the Risk Assessment area: anywhere imported goods containing live hibernating Asian hornet queens are placed.

Very likely – 4

Low – 0 Commodities may potentially be brought in at any time, including months most suitable for establishment.

Moderately – 1

High – 2 Certain commodities (e.g. plant pots) may be placed out doors, assisting transfer. Others may be entirely for indoor use, or for processing – i.e. end-use entirely incompatible with aiding transfer,

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Likely - 2 High – 2 (i) Depends on the type of commodity imported and where it will be used – e.g. indoors versus outdoors – transfer will be much more likely if goods are placed outside and the hornets are not confined on emergence. (ii) Provided a mated queen remains undisturbed long enough to complete hibernation, then she can emerge to found a new colony. (iii) Queen hornets are highly mobile, and very adaptable – they are unlikely to have to travel far from the Pathway to locate suitable habitats. (See Pathway 1. response to Question 1.14) - all resources to meet V. velutina’s basic requirements are widespread throughout the UK, including areas associated with this Pathway. (iv) The distribution of the native European hornet V. crabro within the Risk Assessment area is largely confined to England south of Yorkshire and Wales (Edwards, 1997) – assuming requirements of V. velutina are similar, then likelihood of transfer to a suitable habitat from this pathway will be greatest within these areas.

Pathway 4. Movement of soil associated with plant trade from third countries other than Mediterranean countries. Soil from the EU and Mediterranean countries.

Low - 0 Hibernating mated queens of V. velutina have been recorded as overwintering in soil or leaf litter (Dong & Wang, 1989;

Villemant & Haxaire, 2007; Builles, 2008). In addition, the Asian hornet will sometimes form nests underground (Dong

& Wang, 1989; Martin, 1995; Villement & Haxaire, 2007).

There is thus potential to import nesting V. velutina (larvae and pupae), and/or hibernating adult queens, with soil associated with plant trade from countries where these wasps are present. Plant imports are unlikely to come from nurseries particularly associated with beehives (preferred food source of V. velutina). i.e. likelihood of association with Pathway reduced, but otherwise unknown.

Unlikely – 1 Low - 0 Volume of soil imported depends on the size of the plants in question – whatever is essential to sustain the vitality of the

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plants varies. Hibernating adult V. velutina can cluster in small groups of up to 3 individuals (Mollet et al., 2006; 2007;

Chauzat & Martin, 2009), although size of congregations in soil is unknown: a relatively small volume of soil could harbour several individuals, each mated queen having the potential to establish an entire new hornet colony. By contrast, a very large volume of soil would be needed to conceal even part of a living hornet’s nest. The concentration of V. velutina on the Pathway at origin will also depend on the size of the hornet population in any given area - as many as ten V. velutina nests have been reported in a radius of just 600m (Villemant & Haxaire, 2007) – this is a higher nest concentration than observed for native European hornet V.

crabro (Larsson, 1988).

Medium - 1 Cultivation practices depend on the plant species in question.

Heat treatment and fumigation of soil (required for imports from third countries) is likely to kill hibernating hornet queens. Likelihood of survival depends on the nature of the import in question.

Low – 0 Nesting life stages. It is highly unlikely that even part of an active hornet’s nest could be dug up without detection – such a disturbance would elicit an immediate, conspicuous and aggressive response from adult wasps (see response to Question 2.13). This means that nesting V. velutina are unlikely to be unnoticed if associated with any plants intended for export to UK. Hibernating queens of V. velutina would be much more discrete, and could potentially escape visual inspection. Current legislation regarding soil importation is as follows: (i) Third country imports: Soil and growing media containing soil is prohibited from third countries outside continental Europe, other than from Egypt, Israel, Libya, Morocco and Tunisia (Plant Health Directive 2000/29/EC, 2009). The exception to this is soil intended to sustain the vitality of the plants. In these cases there is a requirement for documentation that the growing medium is free from insects

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and harmful nematodes, and has been subjected to appropriate examination, heat treatment or fumigation and that appropriate measures have been taken to ensure it has been maintained free from harmful organisms (Plant Health Directive 2000/29/EC, 2009). Plant material from third countries (including those where Asian hornets are native) will be inspected on entry into the UK, although it is not possible to inspect every plant. Inspections could potentially pick up V. velutina, but there is no guarantee. Soil associated with plants can be difficult to inspect. However where heat treatment or fumigation is used, this is likely to kill V.

velutina. (ii) EU imports: There are no restrictions on the movement of soil within the EU (or from Egypt, Israel, Libya, Morocco and Tunisia). Soil associated with plants imported from France and Spain where V. velutina is present) will not be inspected.

Very likely – 4

Low - 0 (i) Immature, nesting V. velutina would not be expected to survive: A living hornets nest requires regular feeding, cleaning, ventilation etc. (Perrard et al., 2009); all activities that must be supplied by free-living, foraging colony members which are able to fly to and from the nest. Such conditions would be impossible within this Pathway. (ii) Hibernating queens are highly likely to survive transport/storage. Asian hornet hibernation typically lasts about 4 months (Dong &

Wang, 1989).

Very unlikely – 0

Low – 0 (i) Any immature nesting life-stages of V. velutina imported with soil are likely to starve and die during transport/storage.

Colony growth in absence of a queen V. velutina and attendant workers is impossible. (ii) Hibernating queens of V. velutina are dormant – i.e. not in physiological state at which multiplication will occur.

Moderately high – 2

Medium – 1 The volume of soil imported from third countries where V.

velutina is present is unknown; the volumes of soil imports associated with plants from France and Spain are unknown.

However, plants and associated soil are imported into the UK

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from mainland EU in bulk throughout the year 1.10 How frequent is movement along the

pathway?

Moderately frequent – 2

Low - 0 The frequency of soil imports from third countries where V.

velutina is present is unknown; the frequency of soil imports associated with plants from France and Spain are unknown.

However, plants and associated soil are imported into the UK from mainland EU at all times of the year throughout the year 1.11 How widely could the organism be

distributed throughout the Risk Assessment area?

Very widely – 4

Low – 0 This Pathway has potential to introduce V. velutina throughout the Risk Assessment area: e.g. any garden centre importing plants with soil that may contain live hibernating Asian hornet queens.

Very likely – 4

Low – 0 Soil may potentially be brought in at any time, including months most suitable for establishment.

Likely – 3 Low – 0 Plants may be planted out doors, assisting transfer.

Low – 0 (i) Depends on the type of plants that have been imported and where they will be planted – in nurseries or outside, in areas where bee pollinators are regularly used etc. (ii) Provided a mated queen remains undisturbed long enough to complete hibernation (i.e. soil in which she is concealed is not processed), then she can emerge to found a new colony. (iii) Mated hornet queens are highly mobile and very adaptable – they are unlikely to have to travel far from the Pathway to locate suitable habitats (see Pathway 1 response to Question 1.14) - all resources to meet V. velutina’s basic requirements are widespread throughout the UK, including areas associated with this Pathway. (iv) The distribution of the native European hornet V. crabro within the Risk Assessment area is largely confined to England south of Yorkshire and Wales (Edwards, 1997) – assuming requirements of V. velutina are similar, then likelihood of transfer to a suitable habitat from this pathway will be greatest within these areas.

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Pathway 5. Fruit/cut flower imports.

Likely – 3 Low - 0 (i) Adult V. velutina utilise various fruits and flowers as sources of sugar, and have been recorded as feeding on apples, plums, grapes and Angelica (Mollet et al., 2006; 2007;

Villemant & Haxaire, 2007; Builles, 2008). Like other hornets, they are positively attracted to very ripe fruit (Chang, 1968; Lim et al., 1989; Mishra et al., 1989; Shah & Shah, 1991). There is thus the potential for the Asian hornet to enter the Risk Assessment area with fruits/flowers imported from its known geographical range. (ii) Worker hornets and queens will use fruit as food. Both could be associated with this Pathway, but only queens pose risk of establishment. (iii) There are no records of V. velutina queens being spread by this Pathway. However, there are eight separate records of the Oriental hornet V. orientalis being intercepted on fruit and plant produce imported into the UK (data from Plant Health Interception Records, Fera). (iv) Although at time of interception it was not recorded whether or not these individuals were workers or queens, for the purposes of this Risk Assessment, measurements of the preserved specimens found all of them to exceed 25mm in length (i.e. all were within size range of queens) – dissection to confirm this was not possible due to condition of samples. (v) Most records are not specific about the type(s) of fruit/flower with which the Oriental wasps were associated, interceptions occurring at importers offices, market stalls etc. where a wide variety of produce is likely to be found.

Very unlikely –0

Medium – 1 (i) Large numbers of V. velutina are not expected to be associated with this Pathway. (ii) However, 2 individuals of the Oriental hornet were detected in a single interception, (on imported Ruscus cuttings) (Data from Plant Health Interception Records, Fera). (iii) It is likely that relatively more hornets would associate with this Pathway in the

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autumn. Adult hornets cannot digest animal prey directly, but give this to their larvae which then produce carbohydrate and amino acid rich secretions on which the adults feed (Matsuura

& Yamane, 1990). As the colony declines at the end of the season, workers must seek out other sources of sweet food elsewhere (Chauzat & Martin, 2009). For these reasons V.

velutina is especially attracted to ripe fruit at the end of the summer (Mollet et al., 2006; 2007). (iv) The concentration of V. velutina on the Pathway at origin will also depend on the size of the hornet population in any given fruit growing area - as many as ten V. velutina nests have been reported in a radius of just 600m (Villemant & Haxaire, 2007) – this is a higher nest concentration than observed for native European hornet V. crabro (Larsson, 1988).

Likely – 3 Low - 0 (i) Fruit may be chilled during transport. In theory, this alone would not necessarily kill adult wasps, but the survival statistics for V. velutina at extreme temperatures have not been documented. (ii) Ripening chemicals or insecticides applied to fruits may affect survival, but it is unknown how often and on what fruit-commodities these would be used.

(iii) Regarding records of the import of V. orientalis via this Pathway, at least 4 of the 9 hornets recovered were alive at time of interception. The fact that V. orientalis was able to survive existing commercial/cultivation practices indicates that V. velutina would be likely to do the same.

Low - 0 (i) Imports from third countries: Some fruit imported from third countries is controlled, and must be accompanied by a phytosanitary certificate which states that the material in question has been officially inspected at point of origin, complies with statutory requirements for entry into the EU, is free from quarantine pests and diseases, and is ―substantially free from other harmful organisms‖. Controlled fruits and flowers will be inspected (a representative sample of each consignment) by the Plant Health and Seeds Inspectorate (PHSI), and since live hornets are comparatively large and

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conspicuous in their behaviour, if present in large numbers V.

velutina might be detected. However, since V. velutina is not a listed plant health quarantine pest (Directive EC/2000/29), this species is not specifically targeted during inspections.

Other produce entering the UK from third countries, which is not considered to present a significant risk in terms of quarantine pests and diseases, is unrestricted and not subject to routine plant health controls. V. velutina could thus enter on these fruit/cut flower imports from third countries undetected. (ii) Imports from EU: The majority of fruit and flower imports from the EU are uncontrolled, do not require phytosanitary certification, and could thus enable V. velutina to enter the UK undetected.

Very likely – 4

Low – 0 Adult V. velutina could survive sometime if transported and/or stored with a suitable fruit/flower food source. No precise data is available for this species, but in theory V. velutina could last several days. On at least three occasions adult V.

orientalis have been found live, on fruits imported into the UK, in one case surviving transport/storage from Israel (Plant Health Interception Records, Fera).

Very unlikely – 0

Low – 0 Conditions during transport/storage would not be compatible with nest building and breeding for V. velutina. Numbers of hornets would tend to decrease, due to lack of other (protein) food sources, and sub-optimal temperature, humidity etc.

during confinement.

Very high – 4 Low – 0 Detailed statistics about volume of fruits/plants imported into the UK, and their countries of origin can be found on Eurostat, 2010. (i) Third countries: The UK imports a wide range of fruits and flowers from third countries, including those where V. velutina is known to be present. For example, from China alone, the UK imports at least 19 types of fruit/fruit product.

In 2009, the UK imported over 5 million tonnes of fresh apples and pears from this source, both fruits which are known to be utilised by foraging Asian hornets (Villemant &

Haxaire, 2007). (ii) EU imports: The volume of trade with

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EU is also high (and far less restricted), and includes fruit types utilised by adult V. velutina e.g. in 2009 the UK imported 46,000 tonnes of fresh table grapes from France.

Very frequent – 4

Low – 0 Frequency of import depends on the fruit/plant product in question. However, large volumes of all types of fruit are imported throughout the year (Eurostat, 2010).

Very widely – 4

Low – 0 Imported fruits and flowers are distributed and sold throughout the Risk Assessment area. Oriental hornets travelling on imported fruits/plant products have been intercepted in Birmingham, Hull, Liverpool, Kent, Northamtonshire, Worcester and London (Plant Health Interception Records, Fera)

Very likely – 4

Low – 0 (i) Imports/movements could potentially occur at any time of the year. Fruit hosts known to be used as food sources by V.

velutina are imported into the UK throughout the year from countries known to have Asian hornets (Eurostat, 2010). (ii) Interceptions of Oriental hornets imported into the UK have occurred throughout the year (February, March, April, May, June, December) (Plant Health Interception Records, Fera).

(iii) Inseminated queens arriving early in the season (spring) could establish new nests. (iv) Inseminated queens arriving in the autumn could overwinter in the UK. (V) Irrespective of the date of arrival, worker hornets would not be expected to establish in the Risk Assessement area – this life stage is not capable of reproducing, and is also dependent on a colony of co-workers for survival.

Mediem - 1 Depends on the commodity. h the type of fruit imported:

Dessert apples and pears may be sold from market stalls in the open air, aiding dispersal; strawberries imported for jam- making will be processed accordingly.

Likely – 3 Low – 0 (i) The life stage being imported with fruit/flowers is likely to be adult hornets. Note: these only pose a threat of establishment in the Risk Assessment area if they are mated queens – only these insects are capable of establishing new

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colonies. (ii) Asian hornets imported with controlled fruits/plant products from third countries come in through ports and airports. Should such consignments be left in the open, then wasps could readily disperse from these points of entry. (iii) Similarly, imported fruits/flowers (EU and 3^rd country) are distributed to many different kinds of outlets throughout the Risk Assessment area (supermarkets, processing plants, small scale green-grocers, florists etc.), at least some of which will be out of doors (e.g. market stalls).

(iv) Queen hornets are highly mobile, and very adaptable – they are unlikely to have to travel far to locate suitable habitats – but habitat requirements will vary, depending on time of year at entry: (v) If a mated queen arrives in the autumn, she will need to find a place to hibernate until the following spring. The likelihood of finding suitable hibernation sites is high, given that any small, concealed well- insulated site may suffice. (vi) A mated queen arriving in spring or summer months can found a new colony – (see Pathway 1. response to Question 1.14) - all resources to meet V. velutina’s basic requirements are widespread throughout the UK, including areas associated with this Pathway. (vii) The distribution of the native European hornet V. crabro within the Risk Assessment area is largely confined to England south of Yorkshire and Wales (Edwards, 1997) – assuming requirements of V. velutina are similar, then likelihood of transfer to a suitable habitat from this pathway will be greatest within these areas.

Pathway 6. Movement on freight containers and transport vehicles themselves.

Unlikely – 1 Medium - 1 (i) The potential with this Pathway is that inseminated Asian hornet queens could either travel as active adult hitchhikers, or as dormant hibernating queens. (ii) Asian hornet workers could also travel by this Pathway, but these do not pose a threat of establishment in the Risk Assessment as they are

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incapable of establishing new colonies. (iii) No records were found of V. velutina queens being directly associated with transport vehicles, or of Asian hornet queens using freight or transport vehicles as hibernation sites.

Very unlikely – 0

Low - 0 (i) It is considered unlikely that large numbers of V. velutina would associate with this Pathway at origin, but no records were found to support this assumption. (ii) Records of hornet queens forming swarms are very rare (Mulhauser & Vernier, 1994), and the frequency of such swarming behaviour in Asian hornets is unknown. However, there are reports of other social Hymenoptera (honey bees) forming swarms on ships, and hitchhiking to countries outside their normal range (Tarpy, 2007). (iii) Bee swarms have also occasionally been picked up on ships arriving in the UK (National Bee Unit (NBU) pers. comm.).

Likely – 3 Low - 0 There are no known consistently-used management practices on this Pathway. Some containers may be fumigated during transport, depending on the consignment.

Medium –1 Depends on the lifestage in question: (i) It is highly unlikely that a swarm of Asian hornets would go undetected – these are highly active, often aggressive stinging insects. (ii) By contrast, hibernating queens of V. velutina are much more discrete, and could potentially escape visual inspection.

Medium –1 Depends on the lifestage in question: (i) Under normal circumstances, the lifespan of an adult female V. velutina is 24-142 days, and an adult male 4-60 days (Dong & Wang, 1989), but this assumes access to food, water and shelter. (ii) It is very unlikely that active adult Asian hornets would survive for more than a day or two during transport and storage, especially without water. (iii) Specific data re.

duration of Asian hornet hibernation under natural circumstances is limited, but it typically lasts about 4 months (Dong & Wang, 1989) – far longer than typical duration of transportation. (iv) Length of storage commodity depends on goods involved.

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Very unlikely – 0

Low – 0 (i) Numbers of active adult V. velutina would be more likely to decrease, due to hornets dying during transport/storage (lack of food and water). (ii) Hibernating queens of V.

velutina are dormant – i.e. not in physiological state at which multiplication will occur.

Very high – 4

Low - 0 Unknown. Depends on transport involved. However, traffic of freight/transport vehicles into the Risk Assessment area from areas affected with Asia hornets is high and constant throughoutthe year.

Very high - 4 Low – 0 Unknown. Depends on transport involved. . However, traffic of freight/transport vehicles into the Risk Assessment area from areas affected with Asia hornets is high and constant throughoutthe year.

Very widely – 4

Low – 0 Unknown. Depends on transport involved. However, potentially anywhere in Risk Assessment area.

Very likely – 4

Low – 0 (i) Could potentially arrive at any time of year, depending on origin. (ii) Establishment in Risk Assessment area via this Pathway can only occur if the hornet in question is an inseminated queen – only this life stage can found a new colony. (iii) Inseminated queens arriving early in the season (spring) could establish new nests. (iv) Inseminated queens arriving in the autumn could overwinter in the UK.

Low - 0 By virtue of the Pathway, which involves mobile transport, this will aid distribution. Likelihood of arrival at suitable habitat depends on the transport involved.

Likely – 3 Medium – 1 (i) Adult workers: The length of time which an Asian hornet worker can survive away from her colony is unknown – an individual arriving in the Risk Assessment area via this Pathway would only be expected to survive in the short term, depending on access to food and shelter, but she would not be capable of independent existence long term - this life stage is also dependent on a colony of co-workers for survival. (ii)

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Hornet queens are highly mobile and very adaptable – they are unlikely to have to travel far from the Pathway to locate suitable habitats. (see Pathway 1. response to Question 1.14) - all resources to meet V. velutina’s basic requirements are widespread throughout the UK, including areas associated with this Pathway. (iii) V. velutina queens could potentially fly off a ship or plane on landing, and find a suitable habitat – beekeeping is widespread throughout UK, and is practiced near ports and freight depots. (iv) The distribution of the native European hornet V. crabro within the Risk Assessment area is largely confined to England south of Yorkshire and Wales (Edwards, 1997) – assuming requirements of V.

velutina are similar, then likelihood of transfer to a suitable habitat from this pathway will be greatest within these areas.

Pathway 7. Movement of honey bees: queens and packaged bees (workers) for the purposes of trade. From the EU only this also includes the movement of whole colonies.

Unlikely – 1 Low – 0 (i) Although Asian hornets’ preferred food source is honey bees, V. velutina are comparatively unlikely to be associated with this Pathway. Adult hornet workers do not live inside colonies of A. mellifera, but only enter to raid eggs and larvae.

(ii) Apart from early in the season, when hornets are establishing founder nests, inseminated queens do not enter beehives – inseminated queens are the only life stage that can establish in the Risk Assessment area. (iii) Other life stages of V. velutina (eggs, larvae, pupae) are never associated with adult bees. (iv) Although there are no reports of V. velutina queens hibernating inside overwintering honey bee colonies, other social wasps frequently use honey bee hives as refuges, often hiding spaces between hive crown boards and roofs; in 2009 up to 90% of the NBU’s 130 hives contained at least one inseminated Vespula spp. (germanica or vulgaris) queen during the winter period, and some apiaries contained as many as 40 individuals (pers. comm. Jack Wilford, NBU).

1.4 Is the concentration of the organism on the Very unlikely Low - 0 Precise population concentrations of V. velutina in those

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pathway at origin likely to be high? – 0 countries that export honey bees where Asian hornets are present (France, Spain, China, Hong Kong, India and Thailand) are unknown. However, as many as ten V. velutina nests have been reported in a radius of 600m (Villemant &

Haxaire, 2007). There are no records of V. velutina being concealed and transported when a hive has been moved.

Very likely – 4

Low – 0 Experiences of French beekeepers demonstrate that existing beekeeping practices are unlikely to have any negative effects on V. velutina populations.

Very unlikely – 0

Low – 0 Adult V. velutina are comparatively large, and highly active, and are very likely to be detected in any inspected consignments. The authoritative legal position for the importation of bees into the UK can be found in the appropriate national legislation which is available at:

http://www.opsi.gov.uk/stat.htm and the European Commission legislation may be found at: http://eur- lex.europa.EU/RECH_menu.do?ihmlang=en It is also summarised in document: The Importation of Bees into England – A Guidance note for Importers (Fera, 2009). (i) Third country imports: Honey bees may be imported into the EU from third countries provided that the three notifiable pests of bees in the EU, (Small hive beetle, American Foul Brood, and Tropilaelaps mites), are confirmed as notifiable throughout the exporting country. Only Argentina, Australia and New Zealand currently meet these requirements. V.

velutina is not believed present in these countries (EPPO, 2007). To import honey bees from other third countries, checks have to be made that they are able to comply with the requirements of the EC health certificate. Eligible third countries include the following which are known to have V.

velutina: China, Hong Kong, India and Thailand (Bee Health Policy, 2009). Imports from these countries are restricted to queen bees and no more than 20 attendant workers. All honey bees imported directly into England from a third country must enter through one of two designated Border Inspection Posts